Heavy alcohol use is prevalent among returning Veterans and results in significant physical and psychological burden. One in five returning Veterans screens positive for probable past-year alcohol use disorder (AUD), and few hold positive beliefs about mental health treatment. Moreover, brief interventions for alcohol use demonstrate limited efficacy within this population. Thus, additional strategies are needed to engage and treat returning Veterans who may be at risk for AUD. More than half of returning Veterans who screen positive for hazardous drinking report clinically significant symptoms of insomnia. In turn, insomnia symptoms have been associated with increased risk of alcohol-related problems, perhaps due to insomnia-related impairments in executive functioning, negative emotionality, craving for alcohol, and use of alcohol as a sleep aid. The proposed K23 aims to determine the utility of the first line of treatment for insomnia (Cognitive Behavioral Therapy for Insomnia or CBT-I) in reducing alcohol use and related problems among returning Veterans. Forty- four returning Veterans who indicate risk for problem drinking on the Alcohol Use Disorders Identification Test (AUDIT-C scores ?4/5 for women/men) and have insomnia based on DSM-5 and research diagnostic criteria will participate in a randomized pilot trial. Participants will be randomly assigned to receive personalized normative alcohol feedback in the context of one of two treatment conditions: CBT-I (n = 22) or a time- matched Behavioral Placebo Treatment (BPT; n = 22). Outcomes will be assessed at the end of the active intervention period (6 weeks), mid-treatment (after 3 sessions), and at 3 months post-intervention. Outcomes of interest include insomnia severity, total wake time, sleep quality, drinking quantity/frequency, alcohol-related consequences, executive functioning, negative affect, emotion regulation, craving for alcohol, and use of alcohol as a sleep aid. This research will provide Dr. Miller with mentored training in (1) the methodology of multi-session insomnia treatment research, including daily assessment and mechanistic behavioral trial design; (2) the interplay of sleep and alcohol use disorders; (3) assessment of executive functioning; and (4) longitudinal mixed effects modeling. Training will take place under the mentorship of an impressive team with complimentary areas of expertise. The proposed 5-year career development plan will facilitate Dr. Miller?s transition to independent research by providing her the skills to (a) compete successfully for federal funding to conduct high-quality research, (b) advance our understanding of the etiology of AUD, and (c) contribute uniquely to alcohol addiction prevention and treatment research. The proposed research aims to reduce the harms associated with heavy alcohol use among Veterans by improving the availability of efficacious treatment. It will impact our understanding of the benefits of CBT-I, and it is innovative because it evaluates improvement in insomnia as a mechanism for improvements in AUD. This research is consistent with NIAAA?s initiative to evaluate and promote interventions that prevent the progression of AUD in diverse populations.